Superiority of continuous over intermittent intraoperative nerve monitoring in preventing vocal cord palsy

Background Continuous intraoperative nerve stimulation (IONM) with uninterrupted monitoring is likely better than intermittent IONM in preventing vocal cord palsy after thyroid surgery. Methods This was a comparative study of intermittentversuscontinuous IONM in patients with benign and malignant thyroid disease treated at a tertiary centre over 10 years. Early postoperative and permanent vocal cord palsy rates were estimated. Multivariable logistic regression analysis was used to quantify the contributions of clinical and histopathological variables to early postoperative and permanent vocal cord palsy. Results A total of 6029 patients were included, of whom 3139 underwent continuous and 2890 intermittent IONM. Based on nerves at risk (5208versus5024 nerves), continuous IONM had a 1 center dot 7-fold lower early postoperative vocal cord palsy rate than intermittent monitoring (1 center dot 5versus2 center dot 5 per cent). This translated into a 30-fold lower permanent vocal cord palsy rate (0 center dot 02versus0 center dot 6 per cent). In multivariable logistic regression analysis, continuous IONM independently reduced early postoperative vocal cord palsy 1 center dot 8-fold (odds ratio (OR) 0 center dot 56) and permanent IONM 29 center dot 4-fold (OR 0 center dot 034) compared with intermittent IONM. One permanent vocal cord palsy per 75 center dot 0 early vocal cord palsies was observed with continuous IONM, compared with one per 4 center dot 2 after intermittent IONM. Early postoperative vocal cord palsies were 17 center dot 9-fold less likely to become permanent with continuous than intermittent IONM. Conclusion Continuous IONM is superior to intermittent IONM in preventing vocal cord palsy.